This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Saccharomyces cerevisiae protein Stu1p has an essential role in mitotic spindle function. It is necessary for mitotic spindle formation and maintenance. Stu1p is part of a network of proteins localized at the mitotic spindle midzone. We are attempting to understand the protein-protein interactions within this spindle midzone network, to better understand the establishment and maintenance of the mitotic spindle. Since Stu1p is an essential member of this network, we are interested in understanding whether it interacts with other midzone proteins, and whether these interactions are necessary for Stu1p function.